The present invention relates to a windmill. In particular to a windmill with an aerodynamically shaped foil rotating about a central shaft, wherein the position of the foil relative to the wind is controlled by a tilt assembly and roller unit in operative contact with an inner and outer cam track.
For many years, windmills have been used to harness wind energy for a variety of purposes. Particularly, in the later part of the 19th century and the early part of the 20th century, windmills gained favor for use in pumping water from wells and later for generating electricity. A great deal of interest in these devices existed around this time.
Due to technological innovations, windmills declined in popularity in favor of fossil fuel based sources of energy. However, especially, in rural areas, use of windmills continues to this day. Recently, with increased attention paid to the environmental problems associated with forms of energy that rely on fossil fuels, and with technological innovations associated with the use of renewable energy sources, attention again has returned to windmills as a significant alternative source of energy.
One of the innovations applied to windmills comprises the use of aerodynamically shaped blades or foils, which create lift to more efficiently capture wind energy. The blades utilize a wing shape that creates high pressure on one side of the blade and low pressure on the other. By properly positioning the blades relative to the windxe2x80x94known as the angle of attack, the pressure differential will increase the rotational speed of the windmill, thereby resulting in more efficient operation. Prior art devices have employed a number of means of accomplishing this type of windmill operation, however, heretofore, these devices involve either a complex combination of mechanical components or utilize older technologies that do not translate well to modem economies of scale.
Thus, a need exists for a more efficient and reliable windmill apparatus.
An object of the present invention comprises providing a windmill that utilizes a more efficient and reliable apparatus to maintain the proper angle of attack of an aerodynamically shaped foil relative to the wind.
These and other objects of the present invention will become apparent to those skilled in the art upon reference to the following specification, drawings, and claims.
The present invention intends to overcome the difficulties encountered heretofore. To that end, a windmill is provided wherein the windmill comprises a central rotating shaft with an upper and a lower end opposite thereto. A blade arm is provided with an inward and an outward end opposite thereto, wherein the inward end of the blade arm is connected to the upper end of the rotating shaft. An aerodynamically shaped foil connects to the outward end of the blade arm. A cam frame connects to the central rotating shaft such that the cam frame remains substantially stationary when the central rotating shaft rotates. An outer tilted cam track connects to the cam frame, and an inner tilted cam track connects to the cam frame and is located inside the outer tilted cam track, wherein an axis of tilt of the outer cam track and an axis of tilt of the inner cam frame are transversely aligned. A roller unit is provided comprising an arm connected to the blade arm and extending downward and a pivotable roller connected thereto, wherein the pivotable roller is in operable contact with the inner and the outer cam track such that when the blade arm rotates the pivotable roller pivots between the axes of the inner and outer cam tracks. A tilt assembly connects to the roller unit and to the foil for tilting the foil in response to movement of the roller on the axes of the inner and outer cam tracks in order to maintain an appropriate angle of attack relative to the wind.